diff --git a/Gopkg.toml b/Gopkg.toml
index 24f0f17..ea020b8 100644
--- a/Gopkg.toml
+++ b/Gopkg.toml
@@ -1,6 +1,6 @@
 # Gopkg.toml example
 #
-# Refer to https://github.com/golang/dep/blob/master/docs/Gopkg.toml.md
+# Refer to https://golang.github.io/dep/docs/Gopkg.toml.html
 # for detailed Gopkg.toml documentation.
 #
 # required = ["github.com/user/thing/cmd/thing"]
@@ -25,6 +25,10 @@
 #   unused-packages = true
 
 
+[[constraint]]
+  branch = "master"
+  name = "github.com/corpix/reflect"
+
 [prune]
   go-tests = true
   unused-packages = true